The term "pallet" as used herein means a pallet or other rigid supporting structure which holds a generally planar shape while holding a layer of material, while itself being supported by a fork lift having two spaced forks about 4-6 inches wide, as commonly used to support a load e.g. 36 inches wide, measured in a direction transverse to the direction of extension of the forks.
As used herein, "pallet" includes conventional pallets, e.g. about 3 to 4 inches thick, as well as lesser thickness rigid support plates, such as e.g. pressed fibrous sheets commonly known as Masonite.RTM..
The term "load" refers to one or more layers of units of material (e.g. cased product) which are combined together for simultaneous handling by a single handling device, such as a fork lift handling a pallet load, a platen truck handling a unit load on a slip sheet, or a clamp truck handling a unit load, without a slip sheet, by clamping the load between clamps positioned at the sides of the load.
As used herein, the phrase "steady state" means that product is coming out of the load forming system at the same or a faster rate than product is going into the load forming system.
As used herein "designed throughput capacity" refers to the steady state throughput capacity, in number of cases/units of product per minute, which the respective apparatus can be reasonably expected to handle with a high degree of reliability (e.g. greater than 90% up-time) . In many applications, the reliable throughput capacity is related to the line speed at which the cases advance along the conveyor or other material handling apparatus. The reliable speed of throughput for a given application is a function of, as examples, the type and structure of a corresponding conveyor, the size and structure of the cases being handled, and the nature and length of the path being traversed by the respective element.
When I refer to the number of "cases per minute" processed by the case loading system of the invention, or by a subsystem, I mean the average number of cases per minute when considering routine cycling of the system through its various operating steps, including routine cycling of the feed stream to parallel processing elements of the system.
By "parallel processing elements" I refer to more than one processing element or subsystem where multiple elements perform the same type of operation, but where a given case is processed through only one of the respective processing elements.
In my U.S. Pat. No. 4,704,060, I teach a palletizer/load forming system including an in-feed conveyor, a layer forming station, a transfer plate, and a load forming station, all fixed in location such that units of material to be processed are brought to the layer forming station, and to the transport plate, and must be delivered to the load forming station. Typically, the units of material are received from a production line. The palletizer/load forming system, as taught in the '060 patent, is advantageously used where the volume of material coming from a single production line, arid/or processed through a single in-feed conveyor justifies the cost of the palletizing equipment.
In my U.S. Pat. No. 4,988,264, I teach a depalletizing system wherein the depalletizer used is physically very similar in construction to the palletizer taught in U.S. Pat. No. 4,704,060. However, in e.g. FIGS. 1 and 3 of that teaching, I teach the concept of shuttling a plurality of pallet loads into and out of the in-feed position without necessarily emptying any particular load before shuttling in another load.
In application Ser. No. 08/076,272, I teach in e.g. FIGS. 11A, 12, and 13, the concept of receiving material into the load forming system from at least two in-feed conveyors, with the various in-feed conveyors presenting product from different production lines, potentially presenting a plurality of products which must be kept separated, forming the material so-received into layers in at least two layer forming stations, and depositing the material in layers on pallets in at least two load forming stations.
The '272 invention greatly improves the cost benefit of mechanizing the load forming operation where the output of no single production line justifies a load forming system, but wherein a combination of production lines, if all fed through one load forming system, does justify the equipment expense.
In application Ser. No. 08/100,271, I teach a load forming system having a plurality of layer forming stations, receiving material from a corresponding plurality of production lines, and placing the formed layers on a plurality of load forming stations. A mobile, ground-supported transport vehicle is used to transport the formed layers to the load forming stations, thus obviating need for elevated transport-supporting superstructure to extend along the full length of the path of travel of the transport plate among the several layer forming stations and load forming stations.
It is an object of this invention to provide a load forming system capable of fragmenting, and otherwise processing, the input provided by one or more high speed product conveyors, wherein the feed stream of cases from the product conveyor is fragmented in a layer creating subsystem in the load forming system, and wherein the cases are processed at speeds slower than the speeds encountered on the product conveyor.
It is another object to provide a load forming system having a designed overall throughput capacity, including a layer transfer subsystem, a load creating subsystem, and a layer creating subsystem, the layer creating subsystem having at least two parallel sets of processing elements, and sufficient throughput capacity that the parallel sets of processing elements, less one, have a throughput capacity at least as great as the designed overall throughput capacity of the load forming system.
It is a further object of the invention to provide a case loading system having at least two layer transfer plates for receiving layers formed in a layer forming station, and depositing the layers on loads.
It is yet another object to provide a load forming system having a layer creating subsystem, a load creating subsystem, and a layer transfer subsystem, wherein the layer transfer subsystem includes at least two layer transfer plates, for receiving layers formed in the layer creating subsystem and depositing the layers on loads in the load creating subsystem.
It is still another object of the invention to provide a method of handling cases of product received on a product conveyor, and received into a load forming system, by distributing the cases to more than one in-feed conveyor of a layer creating subsystem, by sensing availability of unused capacity in each of parallel operating elements of the layer creating subsystem, and delivering cases to an operating element having available capacity.
It is finally an object to provide such a method of handling cases of product wherein, as a result of parallel processing in one or more subsystems of the load forming system, the cases are processed at a slower rate in the layer creating subsystem than on the product conveyor.